Czech National Natural Analogue Programme. Václava Havlová Nuclear Research Institute Řež plc. Czech Republic

Transcription

1 Czech National Natural Analogue Programme Václava Havlová Nuclear Research Institute Řež plc. Czech Republic 10th NAWG Workshop 2007 Garching, August 25 26, 2007

2 Ústav jaderného výzkumu Řež a.s. Introduction Natural Analogue Working Group Czech Republic: ALES LACIOK VENDA (VACLAVA) HAVLOVA Most responsibilities L E F T N R I Geochemistry far-field, migration, FUNMIG, LTD, NAWG Comment Proposals Suggestions Projects Co-operation FUNDING

3 Main stakeholders in HLW management in the Czech Republic Government organizations Radioactive Waste Repository Authority (RAWRA) State Office for Nuclear Safety (SONS) Ministry of Environment Other State Authorities needed in decision making process (primarily State Mining Authority) Generators of HLW Czech Power Company (ČEZ) -ČEZ is Nuclear Research Institute Řež plc. main stake-holder Public Ecological movements Individual polititians or group of polititians Public from nuclear site municipalities

4 Ústav jaderného výzkumu Řež a.s. Czech nuclear waste disposal contept Repository: GRANITE 2065???? Source LILW-LL Operation (m 3 ) LILW-LL Decommissioning (m 3 ) SNF (t) EDU ( ) ,937 EDU ( ) -- 2, ETE ( ) ,787 ETE ( ) Total NPP 2,724 3,724 Instit. ( ) Instit. ( ) Total institutions

5 Czech Natural Analogue National Programme (NRI Řež) Last period NAS targets: - The Ruprechtov Natural Analogue Site Research ( ) ANTHROPOGENIC ANALOGUES - Uranium glass study ( ) - Cement material in contact with U-bearing waters

6 Natural analogues definition An occurence of materials or processes which resemble those expected in a proposed geological waste repository (Côme & Chapman, 1986) Natural analogues are defined more by the methodology, used to study and asses them than by any intrinsic physico-chemical properties they may possess. (IAEA, 1989)

7 FUNMIG The Ruprechtov NAS Extensively studied for more than 10 years Bilateral project of NRI (CZ) & GRS (D) U. Noseck (GRS) presentation Funded by Czech Ministry of Trade and Industry (POKROK 1H-PK25), RAWRA (CZ), BMWi (D, 02E 9995), EC (FUNMIG RTDC 2 & 5)

8 The Ruprechtov NAS Erzgebirge Mts. (Krušné hory)

9 The Ruprechtov NAS System - argillaceous clays, - organic matter rich layers (lignite) SW - U mineralization NE - kaolinite - granite Pyroclastic Sediments (argill.) Upper Tertiary Granite Clay/Lignite-Sand Kaolin Middle- Lower Tertiary Carboniferous Fault Zone General flow direction

10 Main tasks to study (relevance for the Safety Case System understanding) Petrological, mineralogical, geochemical and hydrogeological research of the system analogous to overburden sedimentary complexes of host rock (salt, clay, granite) Behaviour of uranium in the sedimentary system Impact of sorption onto system constituents Role of organic matter. Identifying factors controlling the composition and dissollution/degradation in the natural system Impact of organic matter composition and degradation on RN mobility in the natural system Isotopic evidence of processes on the site Method development and system understanding (Multi-method approach)

11 Borehole localisation NA15 NA11 NA13 NA14 LEGEND NA10 NA12 NA6 NA5 NA4 Coal and carbonaceous clays in pyroclastics NA8 NA9 NA7 RP5 HR4 PR4 Pyroclastic sediments (undiff.), argillized Secondary kaolin (Kaolinite clays and sands) RP1 RP3 RP4 RP2 Primary kaolin (kaolinized granite) Granite (slightly kaolinized) Granite (Krusné hory type)

12 Hydrogeological flow regime (δ 18 O, δ 13 C, 14 C,) δ 18 O General flow direction SW-NE Infiltration in granite in western and southern area Mixed waters in underlying granite Hydraulic connection between underlying granite and aquiferous zones in pyroclastic sediments (faults) GW ages: 1,000 more than y

13 Uranium forms in the sediment (µ-xrf and µ-xafs, U(IV)/U(VI)-separation method, sequential extraction) -U(IV) phases (55 90% of U tot ) -U(VI) phases - uraninite (UO 2 ) - ningyoite (U &REE phosphate) - uranyl sulphate - amorphous phase U is intimately associated with As, not with Fe and S

14 Organic matter on the site composition and degradation (FUNMIG RTDC 2 and 5) FUNMIG Rich organic matter layers (up to 40% of lignite) X Low DOC in GW, low content of colloids Balance of sedimentary organic matter (SOM): Low content of natural HA - EXTRACTED Low SOM availibilty High clay sorption afinity (HA sorption)

15 Organic matter (OM) degradation Isotopic signature for two C sources on the site: OM (δ 13 C ~ 25 ) + SEDIMENTARY CARBONATE (δ 13 C ~ 13,5 )

16 Reduction of oxidasing agents (SO 4 2-, NO 3- ) 70 10,0 60 NA8 50 NA12 SO RP1 NA10 RP2 NA13 NA6 NA7 NA4 1,0 PO4 + NO SO4 PO4 NO ,1 0,0 1,0 2,0 3,0 4,0 5,0 DOC (mg/l) Increasing PO increasing DOC + δ 32 SO 4 2- (0,2 3,48 ) microbial SOC degradation

17 Result: Conceptual model of U immobilisation U source: underlaying GRANITE SW NE Sedimentary organic matter in the sediment degrades - DOC is released - SO 4 2-, NO 3 - reduced (formation of FeS 2 ) - PO 3-4 formed by microbial Granite SOC degradation - dissolved As is sorbed onto FeS 2, forming FeAsS precipitate - U(VI) reduction on FeAsS sites Fault Zone U (IV) phosphate/oxide precipitation + formation of As(V) Pyroclastic Sediments (argill.) Clay/Lignite-Sand General flow direction Kaolin Upper Tertiary Middle- Lower Terti Carbonifer

18 MIGRATION 2007 presentations U. Noseck et al.: Identification of U Enrichment Scenarios by Multi-method Characterisation (B6-3) Section 4 B6+B5, Mon Posters: V. Havlova et al. : Uranium forms and the role of organic matter on the Ruprechtov natural analogue site. Multimethod approach. (PB6-3) Section PB6, Tue U. Noseck et al.: IP FUNMIG RTDC 5. (PS2-5). Section PS2. Tue

19 Further subjects to study - characterisation and behaviour of natural HA extracted, including complexation with 233 U - study of organic matter degradation/avalibility and its influence onto U immobilisation -redox changes in the systém due to air intrusion (kaoline quarry opened) - NRI/GRS project preparedx ANY POTENTIAL PARTNERS ARE WELCOME!!!!!!!

20 Uranium glass study ( ) Reprocessing of Czech spent nuclear fuel from NPPs is not finally excluded; Reprocessing of spent fuel from research reactors (NRI 2 reactors) is probable

21 Motivation of the study: Little is known about the dissolution and degradation of anthropogenic glasses in natural environment Moreover, the presence of uranium in glass matrix can allow studying of release of uranium from glass matrix and the role of surface layer.

22 U glass production (Bohemia, 1830 late 30ties) Production: Nothern Bohemia (Adolfov, Kristianov, Harrachov, Silesian part of Krkonose Mts., Jablonec) South Bohemia(near Kasperske Hory town). 2 colours: yellow and green. Fluorescence in UV light. U content: approx wt.%. of U more than 150 t of UO 2 consumed throughout the 19th cent.

23 Klastersky Mlyn near Rejstejn town Jachymov area (Kasperske Hory area; production in of ) U glass samples

24 U glass samples (80 years deposited in slug heap) Alteration layer (el. microscopy): µm (1,25 6,25 µm/year)

25 Trends MATRIX LAYER (microprobe) K 2 O: DEPLETION from 20% to 2 3 % Na 2 O: DEPLETION from 1,5% to 0,1 0,2 % UO 2 : DEPLETION from 2,2% to 0,7 0,8 %, however 10x enrichment on the surface (RBS) resorption(?) SiO 2 : INCREASE from 72% to 80% Variation of P 2 O 5, Al 2 O 5 and MgO close/directly into alteration zone

26 U glass matrix Inhomogeneities: bubbles and spherical formations Non-clear generation: - air - glass diferentiation - He/Rn α-decay products and daughter isotopes (?) Optical microscopy: Structure of glass (75x magnification).

27 U release into soil cover Leaching of glass: release of U increased concentration aureole up to tens ppm of U - 2 peaks: 0,4 0,8 and approx. 1,5 m

28 Soil depth profile Relative beta activity

29 Publications Procházka R. et al. (2002): NATURAL CORROSION OF OLD POTASH GLASS COLOURED WITH URANIUM COMPOUNDS. Ceramics Silikaty, 46 (3), Laciok A. and Reilich P. (2003): ANTHROPOGENIC ANALOGUES IN THE CZECH REPUBLIC _ STUDIES ON GLASS AND CONCRETE MATERIAL. NRI REZ Report.

30 Cement material in contact with U-bearing waters (POTENTIAL) Motivation of the study: - DURABILITY OF MODERN CONCRETE, - CONCRETE/ WATER INTERACTION & - MIGRATION OF RADIONUCLIDES FROM HIGH ACTIVE NATURAL WATER

31 POTENTIAL FOR THE NEW PROJECT Jáchymov (Joachimstall) a place from Maria Curie uraninite originated Svornost mine used for pumping and collecting radioactive water for medical/spa purposes (370 l/min; 12 kbq/l) Concrete basins (3) used for water storage from 1924 and 90ties 1st attempt (2002): samples with surface activity kbq Samples lost during the 1000 year flood in 2002.

32 THANK YOU FOR YOUR ATTENTION!!!